Electric drill holder

ABSTRACT

Disclosed is an electric drill holder which provides a lever function in association with the electric drill, thus enabling one to apply a multiplied force to the drill bit in operation.

United States Patent [191 Kikuchi [111 3,834,828 Sept. 10, 1974 1ELECTRIC DRILL HOLDER [76] Inventor: Yukio Kikuchi, No. 15-10, S-chome,

Tateishi, Katsushika-ku, Tokyo, Japan Filed: Feb. 16, 1973 App]. No.:333,349

[30] Foreign Application Priority Data Feb. 19, 1972 Japan 47-17584 US.Cl. 408/92, 408/712 Int. Cl B23!) 45/14 Field of Search 408/92, 712

References Cited UNITED STATES PATENTS 2,667,092 l/l954 Schaffer 408/925/1966 Meyer 10/1972 Salfer FOREIGN PATENTS OR APPLICATIONS 232,6843/1910 Germany ..408/92 846,277 9/1939 France ..408/92 PrimaryExaminer--Andrew R. Juhasz Assistant ExaminerZ. R. Bilinsky [5 7]ABSTRACT Disclosed is an electric drill holder which provides a leverfunction in association with the electric drill, thus enabling one toapply a multiplied force to the drill bit in operation.

6 Claims, 4 Drawing Figures PATENTH] SEPI 01974 SHEET 1 OF 2 FAIENTEDSEFI 01914 SHEET 2 0F 2 FIG.3

ELECTRIC DRILL HOLDER This invention relates to an electric drillholder, and more particularly to a holder device which provides a leverfunction in association with the electric drill, thus enabling a workerto apply a multiplied force to the drill bit in operation.

In operating an electric drill, a worker grips the handle of the devicein his right hand, and positions the drill bit at a proper place, and atthe same time he must apply the force to the device with his single handto push the drill bit against the workpiece. In this connection thedrill bit of a relatively large diameter cannot be used because ofinsufficient force to the drill bit. The drill bit as large as mm. indiameter is in fact, difficult to handle. This difficulty will beincreased in drilling operation at an elevated place in a high-storiedbuilding as for instance in fixing a sign board to an elevated place. Inthese instances sometimes, a worker extends the full length of his armto hold a relatively heavy device above his head, or sometimes he keepshis body twisted for the whole period of drilling operation. This willcause fatigue, and at the. same time it will put a worker into danger offalling. This danger will be enhanced by the sudden start of the counterrotation of the device body, which is caused by catching and preventingthe drill bit from rotating just before the drill bit has passed throughthe workpiece. In the hope of overcoming the above difficulties, it hasbeen hitherto proposed that an electric magnet be associated with anelectric drill thus magnetically fixing the electric drill to theworkpiece in operation. The combination of the electric magnet with theelectric drill body makes the whole size of the device large and heavy,and therefore the device is difficult to handle. Also, such device isexpensive.

An object of this invention is to provide an electric drill holder whichis free from the defects above mentioned.

The advantages attributable to a unique design of the detachable typeelectric drill holder according to this invention are:

i. the force to push the drill bit against the workpiece can bemultiplied by the lever action of the holder, and the force thusmultiplied is sufficient to allow a rela tively large diameter drill bitto make a hole in the workpiece;

ii. the sudden counter rotation of the device body just before thecompletion of drilling operation is completely eliminated;

iii. the worker can operate the electric drill in an efficient waywithout being fatigued for a relatively long period of operation; and

iv. the worker can easily attach to and detach the holder from theelectric drill. The holder itself, is light, stout, and inexpensive.

Other objects and advantages of this invention will be apparent fromthefollowing description when considered in connection with the attacheddrawings wherein:

FIG. 4 is similar to FIG. 2, showing another embodiment of thisinvention in section.

Referring to the drawings, a conventional electric drill having anelectric motor incorporated therein, is indicated by reference numeral1.. The electric drill has a grip 2 and a chuck 3. The chuck 3 isadapted to receive and clamp a drill bit 4. The neck portion of thedrill body 1 is inserted in and fixed to a male annular member 7 byassociated screws 8. As shown in FIG. 2, the male annular member 7 has amale-threaded projection 6. The male annular member 7 can threadly matewith a female annular member 5. The female annular member has femalethreads 5' on the inner sur face thereof and indentations 9 around theend thereof opposite to the threaded end. The spiral direction ofthreads 6 and 5' (for instance, in the left hand) are opposite to therotating direction of the drill bit (for instance, in the right hand),thus causing the male annular member 7 to threadly mate with the femaleannular member 5 as the consequence of a counter reaction to the drillbit rotation. The female annular member 5 is adapted to receive a ring10. The ring has indentations 11 formed along one circumferential edgethereof and a pair of axles l2 fixed on the peripheral surface thereof,as best shown in FIG. 3.

As mentioned earlier, the drill bit is often caught by the aperture edgejust before the termination of drilling operation, and therefore therotation of the drill bit is forcedly and suddenly stopped, thus causingthe sudden counter rotation of the drill body with a relatively strongforce. As best shown in FIG. 3, the indentations of the female annularmember 5 and associated ring 10 are shaped in such a form that thestrong force above mentioned will cause the annular member andassociated ring to be put into locking condition, thus preventing thecounter rotation of the drill body as described later in detail.Preferably, the indentations 9 and 1 1 is made inthe form of saw-tooth.However, they may be in the triangular form.

The axles 12 are positioned opposite to each other in a diametricaldirection of the ring 10. The ring 10 is pivotally mounted in the collarportion 15 of the holder by inserting the axles 12 in associated holes13. The collar portion 15 has a rod 24 connecting the opposite endsthereof.

As shown in FIG. 1, a hollow handle 17 of the holder suspends from thecollar portion. As is best shown in FIG. 2, a lever 22 is pivotallyconnected to the upper portion of the handle 17 by a pivot pin 16. Thelever 22 has an indented portion 21 in the vicinity of the pivot 16, andthe handle 17 has a raised seat 17' projecting from the inner surfacethereof.

An elongated flexible body such as a length of chain or steel wire 18has a hook 19 attached to one end thereof. The other end of the chain orsteel wire is connected to a spring coil 20 which is positioned at thebottom end of the handle, thus causing the chain or steel wire to bespring-biased at all times. As shown best in FIG. 2, the chain passesaround the pivot pin 16, and then through the space between the indentedportion 21 and the raised seat 17'. The chain 18' will be clampedbetween the indented portion 21 and the raisedseat 17 by pushing thelever 22 against the handle 17, thus preventing further pulling-in ofthe chain into the handle.

As is best shown in FIG. 2, the lever 22 has a hooking projection 25 onthe lower portion thereof. Thehandle 17 has first and second holes inopposite facing relationship. The first hole '28 of the handle is madein the form of slit. A cylindrical latching member 26 is slidablymounted in the handle. The catch hole 27 of the latching member 26 isadapted to receive and catch the hooking projection 25 when the lever ispushed against the handle. The latching member 26 has a finger operatedprojection extending through the second hole of the handle. The latchingmember 26 is spring-biased in such a way that the hooking projection 25and the catch hole 27 are put into the latching condition when thehooking projection 25 is inserted in the catch hole. Thus, the lever 22when pushed against the handle will be kept closed, and at the same timethe chain 18 will be clamped between the indented portion 21 and theseat'=l7. By pushing and moving the finger operated projection of thelatching member against the resilient force of spring, the hookingportion 25 will be released from the catch hole 27. As a result thelever 22 is made free, and at the same time, the full length of thechain 18 will be automatically pulled into the hollow handle under theinfluence of the spring coil 20.

When the electric drill holder is in use, the neck of the drill body 1is firmly fixed to the male annular member 7 by the associated screws 8.The worker holds the grip 2 of the drill body 1 in his right hand,putting the drill bit 4 on a desired position of an object, such as anL-shaped steel body a. Then, the chain 18 is drawn out from the interiorof the handle 17. The hook 19 is then, caught by the object. The chain18 will be tight under the influence of the spring coil 20. Then, thelever 22 is closed with the result that the chain 18 is clamped betweenthe indented portion 21 and the raised seat 17', leaving a desiredlength of the chain out of the handle.

In the drilling operation the worker holds the electric drill 1 in hisright hand and the holder in his left hand, and then he operates theswitch lever 23. As the drill bit is advancing, the worker pulls androtates counterclockwise the handle 17 about the pivot 16 as indicatedby the arrow b in FIG. 1. Thus, the force to pull the handle ismultiplied by power of a lever, and finally the force thus multipliedwill be applied to the drill bit 4 via the axles 12 in the directionOtherwise, an elongated hook accessory 19 may be used in the manner asshown in the broken line in H0. 1. In this instance the handle 17 of theholder must be pushed and rotated clockwise about the rod 24 of thecollar 15, which functions as the fulcrum of the lever system.

As is apparent from the above, in using the hooking chain 18, the lengthof handle 17 and the length portion of the collar extending from thepivot 16 to the hole 12 constitute together a lever system having thepivot 16 as the associated fulcrum. The worker can apply a strong forceto the drill bit simply by rotating the handle counter-clockwise aboutthe pivot pin 16 as indicated by the arrow b. In using'the hookingaccessory 19', the total length of the handle plus collar, and thelength portion of the collar extending from the rod 24 to the hole 12constitute together a lever system having the rod 24 as the associatedfulcrum. Likewise, the worker can apply a multiplied force to the drillbit by rotating clockwise the handle 17 about the rod 24. The worker cancontrol the positioning of the drill bit by his right hand with easebecause his right hand need not be used in applying the force to pushthe drill bit against the workpiece.

As mentioned earlier, the drill bit is often caught by the aperture edgejust before the termination of the drilling operation, causing thesudden counter rotation of the drill body. This counter rotation willnot affect the grip of the electric drill if it is used in associationwith the holder of this invention. Because the counterrotary force willbe reduced to the minimum by the lever action before it exerts on thegrip of the electric drill through the lever system, which consists ofthe radius length of the collar and the full length of the handle plusthe radius length of the collar.

The annular portions 7 and 5 are threaded in such a direction that thecounter action to the drill bit rotation will make the threadlyengagement tight in operation.

Referring now to FIG. 4, there is shown another embodiment of thisinvention. This embodiment is the same as that shown in FIGS. 1 to 3except for the chain clamping mechanism. As shown in the drawing, thecollar portion 15 has an extension 31 suspending from the lower sidethereof. The upper end of the handle 17 is pivotally connected to theextension 31 by a pivot pin 32. The handle 17 has a detent 33 risingfrom the upper end thereof. The detent has an indented portion facingthe extension 31. The handle 17 also has a hollow frustrum collar 34slidably mounted to the shank of the handle. The chain 18 passes throughthe clearance space between the bottom of the collar portion 15 and theundersurface of the ring 10 and through the space between the extension31 and the indented portion of the detent 33 and then the chain 18 comesinto the hollow handle 17. With this arrangement, if the handle 17 isrotated counter-clockwise about the pivot pin 32, the chain 18 will beclamped between the extension 31 and the indented portion of the detent33. Then, the slidable collar 34 is pushed into the remaining spacebetween the extension 31 and the handle 17, thus wedging the handle 17to the extension 31, and positively preventing the chain 18 fromreleasing from the detent 33.

I claim:

1. A holder for an electric drill having a neck portion coaxial with theaxis of the drill comprising a hollow handle element having a collarportion, an annular assembly releasably mounted on the neck portion ofthe drill and provided with means for pivotally mounting said collarportion thereon, the axis of said handle element being at a substantialangle to the axis of said drill, a length of chain extending from thework to be drilled and then at a substantial angle to pass through saidhollow handle element, means for releasably attaching the outer end ofsaid chain to the work to be drilled, means for biasing said chain insaid handle element and releasable means connected to said handleelement for clamping said chain with respect thereto, whereby when saidchain is clamped by said clamping means and when said handle element ispulled away from the work to be drilled the handle element will pivotabout the point where the chain alters direction to pass through saidhandle element and thus exert pressure through said collar and saidannular assembly to assist the drilling operation.

2. A holder as claimed in claim 1 wherein said annular assemblycomprises a male annular member, means for securing said male member tothe neck of the drill, a female annular member releasably secured tosaid male member and provided with indentations projecting axiallythereof, a ring surrounding said female member and having indentationsabout one edge thereof for engagement with the indentations of saidfemale member, said ring member being provided with said means forpivotally mounting said collar portion of said hollow handle element.

3. A holder as claimed in claim 2 wherein said indentations of saidfemale member and said ring are shaped to interlock and thus preventsudden counterclockwise rotation of said drill if the rotation of thedrill bit suddenly stops while drilling.

4. A holder as claimed in claim 1 wherein said releasable chain clampingmeans comprises a lever pivotally mounted on said handle element, saidchain passing over said pivotal connection for said lever and furtherincludes an indented portion on said lever and a raised 6. A holder asclaimed in claim 4 and further comprising latching means for holdingsaid lever in clamping position against said chain.

1. A holder for an electric drill having a neck portion coaxial with theaxis of the drill comprising a hollow handle element having a collarportion, an annular assembly releasably mounted on the neck portion ofthe drill and provided with means for pivotally mounting said collarportion thereon, the axis of said handle element being at a substantialangle to the axis of said drill, a length of chain extending from thework to be drilled and then at a substantial angle to pass through saidhollow handle element, means for releasably attaching the outer end ofsaid chain to the work to be drilled, means for biasing said chain insaid handle element and releasable means connected to said handleelement for clamping said chain with respect thereto, whereby when saidchain is clamped by said clamping means and when said handle element ispulled away from the work to be drilled the handle element will pivotabout the point where the chain alters direction to pass through saidhandle element and thus exert pressure through said collar and saidannular assembly to assist the drilling operation.
 2. A holder asclaimed in claim 1 wherein said annular assembly comprises a maleannular member, means for securing said male member to the neck of thedrill, a female annular member releasably secured to said male memberand provided with indentations projecting axially thereof, a ringsurrounding said female member and having indentations about one edgethereof for engagement with the indentations of said female member, saidring member being provided with said means for pivotally mounting saidcollar portion of said hollow handle element.
 3. A holder as claimed inclaim 2 wherein said indentations of said female member and said ringare shaped to interlock and thus prevent sudden counterclockwiserotation of said drill if the rotation of the drill bit suddenly stopswhile drilling.
 4. A holder as claimed in claim 1 wherein saidreleasable chain clamping means comprises a lever pivotally mounted onsaid handle element, said chain passing over said pivotal connection forsaid lever and further includes an indented portion on said lever and araised portion on the inside of said hollow handle element for engagingsaid chain when said lever is moved into clamping position.
 5. A holderas claimed in claim 1 wherein said releasable chain clamping meanscomprises an extension extending from said collar, detent means attachedto said handle element, means for pivotally mounting said handle memberonto said extension, said chain extending over said last mentionedmeans, and a frustum collar slidably mounted on said handle element forlocking the engagement of said detent means against the chain.
 6. Aholder as claimed in claim 4 and further comprising latching means forholding said lever in clamping position against said chain.